Bright stars of an open cluster

Artist's impression of an open cluster, a type of star cluster consisting of a few hundreds to a few thousands stars immersed in a tenuous nebula. They are found in spiral and irregular galaxies and originate from giant molecular clouds. The stars belonging to an open cluster are all formed at approximately the same time and distance. For this reason, the study of these clusters is of great interest to astronomers because they offer the unique possibility of studying how stars form and evolve as a function of their mass. The Milky Way hosts open clusters within and between the spiral arms. One of the most popular open clusters near Earth is the **Pleiades**, also known as *the seven sisters* (see figure). It consists of hot, middle-aged B-type stars and is visible in the northwest of the constellation Taurus, at a distance of approximately 444 light-years from Earth.  Image credit: NASA/ESA/AURA/Caltech